MITSUBISHI (Dig./Ana. INTERFACE)
M51995AP/FP
SWITCHING REGULATOR CONTROL
DESCRIPTION
M51995A is the primary switching regulator controller which is
especially designed to get the regulated DC voltage from AC power
PIN CONFIGURATION (TOP VIEW)
supply.
This IC can directly drive the MOS-FET with fast rise and fast fall
COLLECTOR
1
16
Vcc
VOUT
2
15
CLM+
EMITTER
3
14
CLM-
VF
4
13
GND
ON/OFF
5
12
CT
It has another big feature of current protection to short and over
OVP
6
11
T-OFF
current,owing to the integrated timer-type protection circuit,if few
DET
7
10
CF
F/B
8
9
T-ON
output pulse.
Type M51995A has the functions of not only high frequency OSC
and fast output drive but also current limit with fast response and
high sensibility so the true "fast switching regulator" can be
realized.
parts are added to the primary side.
The M51995A is equivalent to the M51977 with externally re-
Outline 16P4
settable OVP(over voltage protection)circuit.
FEATURES
COLLECTOR
Vcc
19
CLM+
3
18
CLM-
VF
4
17
GND
5
16
6
•Modified totempole output method with small through current
20
2
EMITTER
•Output rise time 60ns,fall time 40ns
1
VOUT
500kHz operation to MOS FET
•Output current...............................................................±2A
15
ON/OFF
7
14
CT
Compact and light-weight power supply
HEAT SINK PIN
•Small start-up current............................................90µA typ.
•Big difference between "start-up voltage" and "stop voltage"
makes the smoothing capacitor of the power input section small.
HEAT SINK PIN
OVP
•Packages with high power dissipation are used to with-stand the
heat generated by the gate-drive current of MOS FET.
8
13
T-OFF
DET
9
12
CF
F/B
Start-up threshold 16V,stop voltage 10V
10
11
T-ON
Outline 20P2N-A
16-pin DIP,20-pin SOP 1.5W(at 25°C)
Simplified peripheral circuit with protection circuit and built-in
Connect the heat sink pin to GND.
large-capacity totempole output
•High-speed current limiting circuit using pulse-by-pulse
method(Two system of CLM+pin,CLM-pin)
•Protection by intermittent operation of output over current......
..........................................................Timer protection circuit
•Over-voltage protection circuit with an externally re-settable
latch(OVP)
•Protection circuit for output miss action at low supply
voltage(UVLO)
High-performance and highly functional power supply
•Triangular wave oscillator for easy dead time setting
APPLICATION
Feed forward regulator,fly-back regulator
RECOMMENDED OPERATING CONDITIONS
Supply voltage range............................................12 to 36V
Operating frequency.................................less than 500kHz
Oscillator frequency setting resistance
•T-ON pin resistance RON...........................10k to 75kΩ
•T-OFF pin resistance ROFF..........................2k to 30kΩ
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